The Cellular and Mouse Surgical Core (Core A) will provide 1. Dissociated adult and neonatal cardiomyocytes, 2. Cultured cells, 3. Micro-dissected canine heart tissues, and 4. Implantation and monitoring of ECG telemeters. Four of the Projects in the Program will required these services. Dissociation of cardiomyocytes is technically demanding (especially in mice), often resulting in unreliable access to cells. The Anderson laboratory has developed improved methods to reliably produce, and culture cardiomyocytes for use in these Projects. The core facility will streamline necessary tasks and centralize purchasing of reagents and location of incubators and sterile facilities to provide these Projects with reliable access to cells, and tissues. ECG telemetry provides information on arrhythmias in unrestrained and unanesthetized mice and is a significant improvement over previous approaches for monitoring conventional surface ECGs, but is technically demanding. ECG telemetry for mice in Projects 0009 and 0010 will be brought together with dissociation of cardiomyocytes to streamline activities that require similar technical (micro-surgical) skills and are performed by the same individuals.